B737 captain reported receiving a resolution advisory caused by VFR traffic during approach.

Attributes
ACN	1559714
Time
Date	201807
Local Time Of Day	1201-1800
Place
Locale Reference	EWR.Airport
State Reference	NJ
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	B737 Next Generation Undifferentiated
Operating Under FAR Part	Part 121
Flight Phase	Descent
Flight Plan	IFR
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Multiengine Flight Crew Instrument
Experience	Flight Crew Last 90 Days 200 Flight Crew Total 24000 Flight Crew Type 14000
Events
Anomaly	ATC Issue All Types Conflict NMAC Deviation - Procedural Published Material / Policy
Miss Distance	Vertical 400

Narrative:

We were inside dylin on the phlbo arrival at 6;000 feet. Approach was vectoring is on downwind for 22L at ewr. Were given traffic at 10 o'clock; not sure of the distance but it was at least several miles. Traffic was a VFR cherokee at 5;500 feet heading from our left to right. [We] had traffic on TCAS first; altitude showed 400 feet below us. Picked up traffic visually then received a 'monitor vertical speed' RA (resolution advisory). We were above the TCAS pitch area and in level flight so we maintained pitch and altitude. Traffic passed beneath us. ATC said traffic was 500 feet beneath us; TCAS said 400 feet. Received 'clear of conflict.' continued to ewr. I did not notify ATC of the RA as we did not have to deviate from our clearance.

Original NASA ASRS Text

Title: B737 Captain reported receiving a Resolution Advisory caused by VFR traffic during approach.

Narrative: We were inside DYLIN on the PHLBO Arrival at 6;000 feet. Approach was vectoring is on downwind for 22L at EWR. Were given traffic at 10 o'clock; not sure of the distance but it was at least several miles. Traffic was a VFR Cherokee at 5;500 feet heading from our left to right. [We] had traffic on TCAS first; altitude showed 400 feet below us. Picked up traffic visually then received a 'monitor vertical speed' RA (Resolution Advisory). We were above the TCAS pitch area and in level flight so we maintained pitch and altitude. Traffic passed beneath us. ATC said traffic was 500 feet beneath us; TCAS said 400 feet. Received 'clear of conflict.' Continued to EWR. I did not notify ATC of the RA as we did not have to deviate from our clearance.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.